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Stretching or compression can induce significant energetic, geometric, and spectroscopic changes in materials. To fully exploit these effects in the design of mechano- or piezo-chromic materials, self-healing polymers, and other mechanoresponsive devices, a detailed knowledge about the distribution of mechanical strain in the material is essential. Within the past decade, Judgement of Energy DIstribution (JEDI) analysis has emerged as a useful tool for this purpose. Based on the harmonic approximation, the strain energy in each bond length, bond angle, and dihedral angle of the deformed system is calculated using quantum chemical methods. This allows the identification of the force-bearing scaffold of the system, leading to an understanding of mechanochemical processes at the most fundamental level. Here, we present a publicly available code that generalizes the JEDI analysis, which has previously only been available for isolated molecules. Now, the code has been extended to two- and three-dimensional periodic systems, supramolecular clusters, and substructures of chemical systems under various types of deformation. Due to the implementation of JEDI into the Atomic Simulation Environment, the JEDI analysis can be interfaced with a plethora of program packages that allow the calculation of electronic energies for molecular systems and systems with periodic boundary conditions. The automated generation of a color-coded three-dimensional structure via the Visual Molecular Dynamics program allows insightful visual analyses of the force-bearing scaffold of the strained system. [ABSTRACT FROM AUTHOR]

For the use of polymeric electrochromic devices (ECDs) in architectural or automotive applications, the photostability of the electrochromic (EC) polymer is crucial for long‐term durability. In this study, the photostability of the side‐chain modified poly(3,4‐ethylenedioxythiophene) (PEDOT‐EthC6)thin films deposited by roll‐to‐roll slot‐die coating on indium tin oxide coated polyethylene terephtalate (PET‐ITO) is investigated and characterized by UV–vis and IR spectroscopy. Residual iron salt on the EC polymer layer, necessary for the in situ polymerization, and the variation of storage times between processing steps have no influence on the degradation rate during light exposure. The photostability of the thin films is 30% better in an inert atmosphere than in ambient conditions. Different long‐pass filters are applied to enhance the photostability in the colored and the bleached state. The position of the absorption edge strongly affects the photostability and visual appearance/color of the PEDOT‐EthC6 electrodes. The analysis of the CIE L*a*b* color coordinates reveals that a trade‐off between stability and a desirable color is necessary. To prevent UV degradation of the EC polymer in flexible ECDs, sputtered nickel oxide is chosen as the counter electrode material. The hybrid ECD shows no sign of degradation and loss of electrochromic performance after 350 h of light exposure. [ABSTRACT FROM AUTHOR]

Prussian blue (PB) is considered a potential electrochromic material owing to its open structure, simple synthesis and reversible conversion of multicolor, and studies are focused on its color change of transparent 2blue. However, the multicolor conversion of transparent 2blue2 green2yellow has rarely been reported because the alkali metal ion in the existing PB film is lower in concentration than its standard chemical formula, which makes the complete oxidation from PB to Prussian yellow (PY) unachievable. Herein, the Na-rich rhombic Prussian white (PW) is synthesized via the hydrothermal method, and its mechanism of multicolor conversion is studied. Benefitting from the adequate sodium, the PW film exhibits outstanding electrochromic performance with the reversible multicolor change of transparent 2 blue 2 green 2 yellow and excellent cycling stability (52.1% of capacity retention after 300 cycles). Simultaneously, the long cycling stability and high coloration efficiency of the PW film are also revealed in the process of PW 2 PB. In addition, the self-powered electrochromic device with the system of Zn||PW||Pt@CC is constructed, and it realizes fast coloring response time (26.3 s) and high reversibility. The reversible multicolor conversion and excellent cycling stability of the PW film make it a promising candidate for applications such as camouflage and high-performance smart windows. [ABSTRACT FROM AUTHOR]

Owing to the energy-efficient attributes of electrochromic technology, there has been a growing emphasis on the fabrication of electrochromic devices with high-contrast and stable performance. As an electron donor, the deliberate incorporation of oxygen vacancies into an electrochromic material is poised to significantly elevate the film's electrochromic characteristics. In this study, we successfully synthesized one-dimensional W 18 O 49 nanowires thin films with enhanced oxygen vacancies using a straightforward combination of solvothermal reactions and annealing in Ar. In comparison to films annealed in air, those treated in argon (Ar) exhibited a higher concentration of oxygen vacancies, resulting in improved light absorption characteristics. The optimal annealing conditions were determined to be 400 °C for 40 min. Under these conditions, the thin film demonstrates enhanced electrochromic performance, exhibiting a notable 71.6% modulation in transmittance, a 27.2% increase compared to the air condition. It displays a rapid response time (T b = 3.3 s, T c = 3 s), high coloration efficiency (CE = 55.9 cm2 C−1), and excellent cycling stability (with a ΔT retention rate of 93.9% after 750 cycles). [ABSTRACT FROM AUTHOR]

In this study, results on the effect of technological parameters of the nickel(II)‐oxide thin‐film deposition process, obtained through chemical vapor deposition in an argon–oxygen environment using bis‐(ethylcyclopentadienyl)‐nickel (EtCp)2Ni, on their electrochromic properties, are presented. It is shown that the films lose ability to electrochromic coloring in alkaline environments as their thickness increases up to 170 nm. The introduction of small ozone additions of 0.1 vol% O3 into the gas phase leads to a decrease in the NiO films deposition rate, the formation of a rougher layer with an average grain size up to 71.4 nm, capable of coloring in light brown. Additional cathodic treatment of NiO films at a potential of −0.8 V for 30 s in alkaline environments containing fullerene C60(OH)24 leads to the modification of the surface layer and the formation of NiO–C carbon‐containing nanocomposite coatings with enhanced contrast and the ability to retain the colored state after polarization is turned off, i.e., possessing optical memory properties. Using NiO–C nanocomposite and indium–tin–oxide films, which have opposite coloring mechanisms, in the structure of an electrochromic device allows for an increase in the grade of glass darkening, significantly reducing energy consumption, improving operational characteristics, and life span. [ABSTRACT FROM AUTHOR]

Mechanochromic polymers can change their color in response to external force and have shown promising applications in stress sensing and failure warning. They are usually obtained as thin films or bulky specimens. The mechanochromic fibers, which can be used to make smart fabrics, have been seldom reported due to the lack of efficient fabrication techniques. In this work, a general method using photo‐polymerization of microgel solution in a template tube to produce mechanochromic hydrogel fibers is reported. The obtained hydrogel fibers can generate visible and fluorescent color changes upon deformation. The diameter of the mechanochromic fibers can be easily adjusted by using different template tubes. The mechanochromic fibers can be fabricated as long as 1 m. By reducing the fiber diameter or increasing the microgel concentration, the mechanical properties of the mechanochromic fibers can be improved, leading to more obvious mechanochromic behavior. The polymethacrylate (PMA) is further used to coat the hydrogel fibers, prevent the loss of water in the fibers, and increase the storage time. The mechanochromic fibers with multiple fluorescent colors are further fabricated by utilizing different microgel solutions. This work provides an easy and effective method to fabricate mechanochromic fibers with different color change abilities. [ABSTRACT FROM AUTHOR]

Cu(I) complexes have garnered substantial attention in recent years because of their intriguing photophysical properties and their applications in different fields. Herein, we have reported a new four‐coordinated heteroleptic Cu(I) complex using dicnq, a 1,10‐phenanthroline‐based cyno‐substituted ligand, and Xantphos, a bulky as well as rigid chelating diphosphine ligand. The synthesized complex is characterized by multinuclear NMR and HRMS and described as [Cu (Xantphos)(dicnq)]PF6 (1). Complex 1 exhibits absorption within the range of 380–500 nm and emits around 700 nm, attributed to the metal‐to‐ligand charge transfer transition. Theoretical calculations suggest that the HOMO is predominantly located on the Cu(I) center, whereas LUMO is associated with the dicnq ligand. Further, 1 was found to show vapochromic behavior and blue‐shifted emission was observed in the presence of solvent vapors which can show π–π interaction with dicnq. Notably, the complex demonstrates electrochromic activity, prompting the fabrication of a device (ITO/P3HT/Cu complex/ITO) for an in‐depth exploration of its electrochromic properties. The working potential range for the device was found to be ±3 V. On and Off states show the device has an impressive contrast ratio of ~40% and 38% at 520 and 800 nm, respectively. In addition to this, the device shows rapid coloration and bleaching times of 0.8 and 0.5 s, respectively. In terms of contrast, switching speed, stability, and efficiency values at two different wavelengths, the device shows good electrochromic results. [ABSTRACT FROM AUTHOR]

In the pursuit of sustainable technology, the synthesis of a novel biopolymer, C‐pBPV, through the polymerization of carboxymethyl cellulose sodium salt (CMC‐Na) and viologen (BPV), with ammonium persulfate as an initiator is presented. This groundbreaking process not only promises an eco‐friendly approach but also opens avenues for advanced applications in electrochromic devices (ECDs), particularly in smart windows, displays, and beyond. Departing from conventional multi‐layered approaches, the study underscores the significance of a single‐layer material. C‐pBPV serves both as an electro‐chrome and an electrolyte, making it a compelling material for ECDs. It is used to create a gel‐based electrochromic device G1 with exceptional bistable properties. Following, a systematically controllable device, G2 is accomplished, to enhance color‐switching capabilities by adding vitamin C as an electron mediator. Both devices exhibited outstanding electrochromic properties, showcasing dual‐band absorption in the Vis‐NIR region, with color transitions from transparency to a striking purple state at low voltages. Embracing an all‐in‐one layer configuration, this study set the stage for next‐generation smart windows that not only regulate solar light for energy conservation but also pioneer a more compact, user‐friendly design, prioritizing visual comfort, sustainability, and a tailored user experience. [ABSTRACT FROM AUTHOR]

The nitrogen–hybridization/pyramidalization of two solvated N‐tosylisoindolinone derivatives having chiral residues in adjacent (I) or adjacent and distal (II) position has been investigated by a theoretical‐computational procedure based on Molecular Dynamics simulations and Quantum–Chemical calculations. After validation of our methodology in providing a reliable repertory of conformations by modeling the electronic circular dichroism (EDC) spectra, the electronic features associated with N‐pyramidalization were further characterized through Natural Bond Order (NBO) analysis. Comparing against the N‐geometry observed in crystal structures as a reference, our findings reveal that the presence of neighbouring chiral centers induces a more pronounced N‐pyramidalization in solution than in the solid state, both in I and II. Furthermore, NBO analysis confirms that the N‐lactam mostly retains the sp2 character but exhibits slight configurational distortion (ξI=13°; ξII=21°), which significantly influences the chiroptical activities observed in ECD spectra of I and II. This substantiates the N‐lactams as configurationally stable chiral centers. [ABSTRACT FROM AUTHOR]

The effects of boiling water treatment on the physical properties of Quercus variabilis virgin cork (Qv VC) were examined and compared with those of Quercus suber reproduction cork (Qs RC). The water treatment was conducted at 100 °C for 1 h. Qv VC showed a significantly higher dimensional change in the three directions and lower weight loss than Qs RC by boiling water treatment. Untreated and boiled Qv VC showed higher density, air-dried moisture content, red/green (a*) and yellow/blue (b*) chromaticity, overall color change, shrinkage in all three directions, moisture adsorption on the entire surface, and swelling per 1% moisture content than untreated and boiled Qs RC. However, the lightness (L*) and water absorption on each surface were higher for Qs RC than for Qv VC. Moisture adsorption on each surface was comparable before and after heat treatment for both species. After boiling water treatment, the air-dried moisture content, dimensions, volume shrinkage, water absorption, and moisture adsorption on each surface and the entire surface increased, whereas L*, a*, b*, and swelling per 1% moisture content decreased. The results of the present study could be useful for further utilization of Qv cork growing in Korea. [ABSTRACT FROM AUTHOR]

The thermochromic properties of vanadium dioxide (VO 2) hold great promise for applications in smart glass windows. VO 2 films exhibit a high phase transition temperature (T c), low visible transmission (T lum), and low solar modulating ability (ΔT sol), making them inadequate for the requirements of smart glass windows. While some improvement in VO 2 film performance can be achieved through single-element doping, these limited enhancements still fall short of ideal results. Therefore, there is a pressing need for the improvement of VO 2 films. In this study, we utilized the sol-gel method to prepare VO 2 samples simultaneously doped with three elements: W, Sn, and Zr. Microscopic characterization confirmed the successful incorporation of these elements. Optical measurements, including ultraviolet–visible–near-infrared spectroscopy, were conducted to assess the optical properties of the films. Ultimately, outstanding T lum (69%) and ΔT sol (14%) were achieved, along with an appropriate T c (27.6 °C). Energy consumption simulations were performed using the EnergyPlus model with experimental data, revealing that compared to conventional glass, VO 2 glass reduces total cooling energy consumption by 9.8%. In comparison to previous work, the multi-element-doped films push the performance limits of VO 2 films, offering a viable approach for fabricating superior VO 2 smart glass windows. [Display omitted] [ABSTRACT FROM AUTHOR]

To pursuit advancing electrochromic technology, the preparation of a novel hierarchical‐porous NiOx‐decorated ITO transparent conductive electrode was developed through the vapor‐assisted conversion and subsequent calcination processes. The modified transparent electrode exhibited advantages in the electrodeposition of conductive polymer films, which significantly enhanced electrochromic cycling stability. Moreover, the complementary electrochromic device based on NiOx‐decorated ITO transparent electrode was fabricated, demonstrating rapid response time (1.75 s for coloration and 0.87 s for bleaching), high optical contrast (53.4 %), and remarkable cycling stability (90 % optical contrast retention over 2000 cycles). This finding holds prominent potential for applications in related fields. [ABSTRACT FROM AUTHOR]

Electrochromic devices (ECDs) possess the performance advantages in terms of color adjustability, low power consumption, and visual friendliness, emerging as one of the ideal candidates for energy‐efficient smart windows, next‐generation displays, and wearable electronics. The optical and electrical characteristics of ECDs can be adjusted by modifying the materials or structure of devices. This review summarizes the recent developments of innovative technologies and key materials of ECDs for display applications, highlighting the key issues and development trends in this area. [ABSTRACT FROM AUTHOR]

Electrochromic (EC) displays with electronically regulating the transmittance of solar radiation offer the opportunity to increase the energy efficiency of the building and electronic products and improve the comfort and lifestyle of people. Despite the unique merit and vast application potential of EC technologies, long- awaited EC windows and related visual content displays have not been fully commercialized due to unsatisfactory production cost, durability, color, and complex fabrication processes. Here we develop a unique EC strategy and system based on the natural host and guest interactions to address the above issues. A completely reusable and sustainable EC device has been fabricated with potential advantages of extremely low cost, ideal user- /environment friendly property, and excellent optical modulation, which is benefited from the extracted biomass EC materials and reusable transparent electrodes involved in the system. The as- prepared EC window and nonemissive transparent display also show comprehensively excellent properties: high transmittance change (>85%), broad spectra modulation covering Ultraviolet (UV), Visible (Vis) to Infrared (IR) ranges, high durability (no attenuation under UV radiation for more than 1.5 mo), low open voltage (0.9 V), excellent reusability (>1,200 cycles) of the device's key components and reversibility (>4,000 cycles) with a large transmittance change, and pleasant multicolor. It is anticipated that unconventional exploration and design principles of dynamic host--guest interactions can provide unique insight into different energy- saving and sustainable optoelectronic applications. [ABSTRACT FROM AUTHOR]

Electrochromic (EC) technology is regarded as one of the most promising candidates for next-generation reflective displays, owing to its advantages of outstanding color adjustability, low energy consumption, vivid color, and flexibility, etc. However, current EC reflective displays are seriously restricted by the complicated and expensive patterned methods. Herein, a facile and low-cost route is developed to achieve the EC reflective displays, which is fabricated based on the combination of an easily-obtained EC material of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and an efficient photo-crosslinked additive (2,4-hexadiyne-1,6-diol, HDDO). The micrometer-scale patterns (<50 µm) can be achieved by the in situ photo-crosslinked process. As-prepared EC devices show great performances containing fast response (<0.5 s), good reversibility (>10 000 cycles) and high coloration efficiency (274.75 cm² C-1). More importantly, the applications in the EC logo, QR code, and price tag are demonstrated successfully. Overall, the current exploration suggests an efficient, low-cost, and facile method to produce patterned EC devices with high performance, which can undoubtedly promote the further development and application of EC reflective displays. [ABSTRACT FROM AUTHOR]

The interest in all solid organic based electrochromic devices (ECDs) is on the increase. This is because these devices offer the applicability of electrochromic materials in products such as smart sensors, smart windows, flexible wearables and energy storage devices. The use of quasi‐solid electrolytes for the construction of these ECDs is attractive because of their ease of preparation, availability, low cost, improve electrochromic performance, good ionic conductivity and prevention of leakages in ECDs. Hence, in this review, a detailed discussion is presented on the progress in the development of semi‐solid electrolytes for ECDs fabrication. The preparation of the most common electrolytes that have been applied for organic based ECDs are summarized. Particular attention is given to efforts and strategies that have been adopted to improve the efficiency of quasi‐solid electrolytes. Importantly, knowledge gaps that warrant further research are clearly identified and recommendations for future works are suggested. This review will be very beneficial for both established and new researchers in the field of electrochromic devices and material science. [ABSTRACT FROM AUTHOR]

As the proportion of buildings energy consumption increases, the issue of low energy utilization efficiency becomes increasingly prominent. Approximately 45% of the energy is lost through doors and windows, a significant concern that has drawn society's attention to the potential of electrochromic technology, which can regulate light transmittance and absorption effectively. Specifically, dual‐band electrochromic materials offer a promising solution to this issue, as they can manipulate the transmission ratios of visible (VIS) and near‐infrared (NIR) light to obtain "bright," "cold," "warm," and "dark" independent modes. However, research on dual‐band electrochromic materials and smart windows is still infant, and many challenges including performance and assembly issues, are significant obstacles to the advancement and application of this technology. This review clarifies the basic characteristics of dual‐band electrochromic materials and smart windows, including configurations, operational mechanisms, and performance assessment parameters. In‐depth examination of potential dual‐band electrochromic materials and methods for achieving independent modulation is provided, along with an analysis of the challenges and potential solutions for performance and assembly issues. Finally, the future prospects of dual‐band electrochromic smart windows (ESWs) are underscored. The hope is to eventually facilitate the commercial application of these windows, which can significantly contribute to the creation of modern, energy‐efficient buildings. [ABSTRACT FROM AUTHOR]

Electrochromic smart windows are promising for building energy savings due to their dynamic regulation of the solar spectrum. Restricted by materials or traditional complementary device configuration, precisely and independently controlling of visible (VIS) and near‐infrared (NIR) light is still on the drawing board. Herein, a novel Zn2+ electrochemically active Ce4W9O33 electrode is reported, which demonstrates three distinct states, including VIS and NIR transparent "bright and warm" state, VIS and NIR opaque "dark and cool" state, VIS transparent and NIR opaque "bright and cool" state. A dual‐operation mode electrochromic platform is also presented by integrating Ce4W9O33/NiO complementary device and Zn anode‐based electrochromic device (Ce4W9O33/Zn/NiO device). Such a platform enables an added VIS opaque and NIR transparent "dark and warm" state, thus realizing four color states through individually controlling Ce4W9O33 and NiO electrodes, respectively. These results present an effective approach for facilitating electrochromic windows more intelligent to weather/season conditions and personal preferences. [ABSTRACT FROM AUTHOR]

Electrically triggered color‐changing materials, termed as electrochromic materials, offer precise and programmable color transistions through the manipulation of electric field frequency and amplitude. They are used as displays, sensors, military camouflage, wearable devices, and anticounterfeiting materials. Their future advancements depend on clear understanding of the color change mechanisms and pros/cons between different electrochromic materials. To this end, we starts by categorizing electrochromism into two classes according to color production mechanism: chemical color‐based and physical color‐based. Within the former, color emerges from chemical molecules selectively absorbing specific wavelengths of light and color changes stem from electrochemical redox reactions. The latter, meanwhile, hinges upon electrically induced alterations in the geometries, dimensions, or arrangements of nano/micro structures, such as photonic crystals and plasmonic nanostructures. The principles of color changes in both categories are detailed, and compare their differences in terms of response time, operating voltage, degree of color change, and stability. At the end, their applications will be discussed spanning from smart windows to color display, dynamic camouflage, energy storage, and thermal management. This critical review is aimed to provide multidisciplinary insights that will benefit both novices and seasoned experts engaged in fundamental exploration or practical investigations of electrochromic materials. [ABSTRACT FROM AUTHOR]

Electrochromic batteries as emerging smart energy devices are highly sought after owing to their real‐time energy monitoring through visual color conversion. However, their large‐scale applicability is hindered by insufficient capacity, inadequate cycling stability, and limited color variation. Herein, a flexible Zn‐ion electrochromic battery (ZIEB) was assembled with sodium vanadate (VONa+) cathode, ion‐redistributing hydrogel electrolyte, and Zn anode to address these challenges. The electrolyte contains anchored −SO3− and ‐NH3+, which facilitates ionic transportation and prevents Zn dendrite formation by promoting orientated Zn2+ deposition on the Zn (002) surface. The ZIEB exhibits a continuous reversible color transition, ranging from fully charged orange to mid‐charged brown and drained green. It also demonstrates a high specific capacity of 302.4 mAh ⋅ g−1 at 0.05 A ⋅ g−1 with a capacity retention of 96.3 % after 500 cycles at 3 A ⋅ g−1. Additionally, the ZIEB maintains stable energy output even under bending, rolling, knotting, and twisting. This work paves a new strategy for the design of smart energy devices in wearable electronics. [ABSTRACT FROM AUTHOR]

Metal based electroreflective devices (MERDs) have gained wide attention in recent years in the fields of smart windows and automotive glass due to their excellent photo-thermal modulation capability in the visible and near-infrared wavelength bands due to their high reflectivity. However, the high porosity due to the island-like growth of silver particles makes the devices susceptible to electrodeposited film breakage during prolonged energization or bleaching. This will seriously affect the effectiveness and stability of the device. In this paper, it is shown that the problem of Ag electrodeposition film fragmentation can be effectively overcome by replacing dimethyl sulfoxide solvent by N-methylpyrrolidone (NMP). The optical constants during film deposition were tested by the spectroscopic ellipsometry technique, and the porosity was calculated (reduced by 21.6%). The results show that MERDs with NMP as the solvent have more and more dispersed silver deposition sites, which leads to lower porosity of the silver deposited film during the deposition process. In addition, the lower turn-on voltage, greater contrast, longer memory effect, and greater coloring efficiency reveal that they are more promising for energy-saving applications. [ABSTRACT FROM AUTHOR]

WO 3 based electrochromic device (ECD) is becoming the mostly-used one for smart windows, however, in WO 3 tinted state, the intrinsically deep blue and strong infrared (IR) light absorption, resulting in a habitant discomfortableness and also an enhanced thermal gain from the heated device surface, severely restrict its diversified applications. Herein, we firstly conduct a kind of columnarly-grown and amorphous WO 3 film with high concentration of niobium doping (Nb/(Nb+W) = 54.1 at.%). This film is fabricated via sputtering a home-made ceramic target, and subsequently improved by a rapid thermal annealing (RTA) process. Comparing with the conventional WO 3 , the newly-established system owns not only basic EC properties comprising large light modulation range, fast response, and long-term electrochemically cyclic stability, but also a neutral-tinted color (a * = −1.5, b * = 1.0) as well as a relatively lower IR absorption (63.7 %) in tinted state. These outstanding performances enable the assembled ECD with neutral color (a * = 0.6, b * = −2.7) and a higher energy efficiency in cutting down the interior space air temperature about 4.3 °C in its fully-tinted state, underscoring the potential of the tungsten-niobium-oxygen for commercially viable ECDs. [ABSTRACT FROM AUTHOR]

Diarylethene (DAE) is one of the most widely used functional units for electrochromic or photochromic materials. To better understand the molecular modification effects on the electrochromic and photochromic properties of DAE, two modification strategies, substitution with functional groups or heteroatoms, were investigated theoretically by density functional theory calculations. It is found that red-shifted absorption spectra caused by a decreased highest occupied molecular orbital–lowest unoccupied molecular orbital energy gap and S0 → S1 transition energy during the ring-closing reaction become more significant by adding different functional substituents. In addition, for two isomers, the energy gap and S0 → S1 transition energy decreased by heteroatom substitution of S atoms with O or NH, while they increased by replacing two S atoms with CH2. For intramolecular isomerization, one-electron excitation is the most effective way to trigger the closed-ring (O → C) reaction, while the open-ring (C → O) reaction occurs most readily in the presence of one-electron reduction. Moreover, it is confirmed that substitution with strong electron donating groups (–OCH3/–NH2) or with one O/two CH2 heteroatoms leads to a more favorable closed-ring (O → C) reaction. Functionalized with strong electron-withdrawing groups (–NO2 and –COOH) or one/two NH heteroatom substitutions, the open-ring (C → O) reaction is easier. Our results confirmed that the photochromic and electrochromic properties of DAE can be tuned effectively by molecular modifications, which provides theoretical guidance for the design of new DAE-based photochromic/electrochromic materials. [ABSTRACT FROM AUTHOR]

An organic–inorganic hybrid electrochromic device was fabricated by combining the films of hydrothermally synthesized tungsten oxide (WO3) with electrodeposited polypyrrole. Before making a device, these deposited thin films were characterized using scanning electron microscopy, infrared spectroscopy, and Raman spectroscopy techniques. Thereafter, a solid-state organic–inorganic electrochromic device was fabricated, which shows reversible switching between coloration and bleaching states with a very small external bias voltage (±1 V) and excellent cyclic stability up to 500 s with a negligible amount of transmission loss. In situ electrochemical studies show that the device has enhanced switching speed (1.1/1.8 s), and optical contrast of more than 47% at the wavelength of 650 nm. Furthermore, the optimized electrochromic device displays enhanced coloration efficiency up to ∼304 cm2/C. All these results open a new door for increasing the performance of a single-layered device by combining it with complementary electrodes. [ABSTRACT FROM AUTHOR]

Electrochromic (EC) mirrors fabricated using the electrodeposition of metals can dynamically transition between reflective and transparent states via the deposition and dissolution of the employed metals. In particular, the incorporation of an EC counter electrode enables the realization of an absorptive state under optimized applied voltage. Herein, we present reversible EC mirrors composed of Ag and WO 3 layers as the two electrodes, highlighting their EC properties in three optical transformation modes: transparent, reflective, and absorptive. The formation of Ag layers under optimized deposition conditions was confirmed, and the electrodeposited WO 3 layers exhibited compact or porous structures depending on the deposition conditions. The prepared Ag–WO 3 EC mirrors showed substantial transmittance modulation during the reflecting (53.7%) and coloring (63.5%) process. Interestingly, in comparison to the compact WO 3 , the EC mirrors with porous WO 3 layers exhibited dark-gray coloration in the reduced state, which was attributed to the localized surface plasmon resonance effect caused by codeposited Ag particles. [ABSTRACT FROM AUTHOR]

[Display omitted] Electrochromic devices (ECD) are widely used to regulate the transmittance of sunlight by applying a small voltage, but the drawbacks like complex layer-by-layer preparation procedures and inconvenient assembling process still exist. To address these problems, gel or solution-type all-in-one ECDs were recently developed for the simple structure, however, the leakage risk and absence of flexible large-area production have limited real applications. Herein, a novel all-solid-state and all-in-one flexible ECD was reported by originally developed polymer dispersed electrochromic device (PDECD) strategy. This all-solid-state flexible ECD could be efficiently prepared only by one step of phase separation without any extra treatment, and demonstrated outstanding stability (92.1 % of original ΔT remained after 10,000 cycles), high coloration efficiency (197 cm2/C), low power consumption (86.4 μW/cm2) and satisfied response time (≤12 s). Meanwhile, the stored power in ECD during coloring process could drive a LED with excellent cyclic stability (93 % of original capacity remained after 3000 cycles), implying that ECD could also serve as an idea electrochromic supercapacitor. What'more, a reported largest viologen-based all-solid-state flexible ECD (17.8 × 13.2 cm2) with robust bending resistance (up to 1000 bending cycles) was successfully fabricated with industrial roller coating technique, which indicated the huge potential in real world. [ABSTRACT FROM AUTHOR]

Electrochromic devices (ECDs) based on tungsten trioxide (WO 3) have garnered significant attention in the areas of smart windows, dynamic display, low-power displays, and in other advanced sectors. The electrochromic property of WO 3 is primarily influenced by both electron conduction and ion diffusion processes. This research investigates on the influence of rapid thermal annealing (RTA) on the electrochromic performance of RF sputtered tungsten oxide thin films, which relies on ion diffusion process. RTA treated film showed a mixture of amorphous and crystalline (monoclinic), heterostructure phase. Structural, compositional, electrical, optical, morphological, and electrochromic studies were carried out using various techniques. Based on the electrochromic analysis, WO 3 thin films, RTA treated at 300°C showed higher diffusion coefficient with larger optical modulation (ΔT) of 80 % due the formation of heterostructure with more oxygen vacancies. We hope that this research could propose the possibility for developing high-performance electrochromic smart windows. [ABSTRACT FROM AUTHOR]

Smart chromic materials reacting to physicochemical stimuli are widely applied in optical switches, smart windows, and chemical sensors. Currently, most materials only respond to a single stimulus, but those that respond to multiple external stimuli are still in the minority. Herein, we report a novel porous zinc tungstate@metaloxoviologen framework [Zn3(Bcbpy)6(H2O)2]-[ZnW12O40]·6H2O (ZnW12@MV, H2BcbpyCl2 = 1,1′-bis(3-carboxybenzyl)-4,4′-bipyridinium dichloride), which shows multiple stimulus-responsive properties due to a combination of different functional motifs, namely, viologen electron acceptors, luminescent zinc–oxygen-clusters, porous cationic frameworks, and ZnW12O406− electron donors. Generally, the large-sized polyoxometalate (POM) anions serving as structure-directing agents can easily direct the formation of the oligomeric metaloxoviologen cations, mainly because POMs may break down some linkages leaving larger spaces for themselves. The large ZnW12O406− anions in ZnW12@MV are encapsulated into three-dimensional (3D) metaloxoviologen frameworks built up from the linkages of trinuclear zinc–oxygen clusters and Bcbpy viologens, which offer the first example of a 3D metaloxoviologen framework induced by large-sized POM anions. ZnW12@MV shows a reversible chromic response to X-ray/UV and electricity via different stimulus-induced electron transfers between electron-rich POM anions and electron-deficient metaloxoviologen frameworks, whereas the coloration changes are ascribed to the formation of radical and mixed-valence colored state ZnW12O406− species. The photochromic behavior is accompanied by photoluminescence quenching. The discriminative response to different-sized amines is attributed to the formation of viologen radicals through host–guest electron transfer. These results indicate that the multi-stimulus response ZnW12@MV can be applied in electrochromic devices, inkless erasable printing, and the detection of amines. [ABSTRACT FROM AUTHOR]

The electrochromic (EC) polymer poly (3,4‐(2,2‐dimethylpropylenedioxy)thiophene) (PProDOT‐Me2) is expected to be used in flexible e‐paper displays because of its great optical modulation ability and inherent flexibility. While the EC effect is primarily determined by the anions and cations in the electrolyte, yet suffers from inorganic salt based on monovalent Li+ cations and corresponding anions, such as lithium perchlorate(LiClO4), lithium bis(trifluoromethane sulfonyl) imide (LiTFSI), and lithium trifluoromethane sulfonate (LiTRIF), which may impact the overall EC performance of the EC device caused by insufficient ion doping/de‐doping processes. Herein, the divalent viologen cation‐based ionogel (VGE) is developed to tackle the challenge. Owing to its more anions design, the doping/de‐doping process in the PProDOT‐Me2 is more sufficient, thereby enhancing the optical modulation range (ΔR = 39.4%) of PProDOT‐Me2, compared to monovalent Li+ cation‐based ionogel (ΔR = 13.3%). Meanwhile, the VGE has good interface contact with PProDOT‐Me2 and the flexible electrode, which makes the VGE‐based EC device (V‐ECD) exhibit commendable mechanical stability. To demonstrate the potential application in flexible e‐paper displays, the simple eight‐digit EC display device is assembled from seven V‐ECDs, each of which hasa high switching speed, robust cycling stability, and low operating energy consumption. [ABSTRACT FROM AUTHOR]

Electrochromic technology that enables modulation of a material's optical properties by application of an applied voltage is utilized in smart windows. However, avoiding water absorption by lithium salt in the electrolyte necessitates complex encapsulated device assemblies that must be constructed under strict atmosphere conditions and are largely unrepairable. Herein, a lithium‐salt‐free, hydrophobic, solid‐state poly(ionic liquid) electrolyte based on strong C─F bonds that exhibits low polarizability, low moisture absorption, and a wide electrochemical window, allowing the fabrication of unencapsulated electrochromic devices with outstanding long‐term cycling and environmental stability are presented. Intimate contact between the electrolyte and the electrode is achieved through integrated in situ polymerization, providing an interface with multiple molecular interactions that impart robust adhesion, efficient ion transport, and excellent stability. To demonstrate the potential of this electrolyte for cost‐effective electrochromic smart windows, low‐cost (≈110 USD m−2), unencapsulated, removable, electrochromic "window tint film" with customizable dimensions and shapes are fabricated. [ABSTRACT FROM AUTHOR]

Electrochromic devices (ECDs) have attracted substantial attention on account of their unique characteristics and prosperous applications. However, their monotonous color modification remains a momentous challenge that significantly restricts their application scope. Integrating structural colors that arise from the interaction between light and periodic micro/nanostructures with electrochromic materials (ECMs) turns out to be an effective approach to enhancing the comprehensive performance of ECDs more than the coloration effectiveness. This review provides an overview on the recent burgeoning development of structural color ECDs regarding strategies and applications. The performance parameters of ECDs and physical principles regarding the generation of structural colors are introduced. Then, strategies that introduce structural colors into ECDs are discussed according to the category of chromogenic micro/nanostructures, namely, gratings, (single‐layer and multilayer) thin films, photonic crystals, plasmonic metasurfaces, and composite structures. The current state‐of‐the‐art research activities of structural color ECDs for display application including segmented and pixelated devices are also presented. Additionally, the future perspective of structural color ECDs with respect of major challenges and potential solutions is proposed. [ABSTRACT FROM AUTHOR]

Color reproduction through subtractive synthesis is achieved by combining the three primary colors cyan, magenta, and yellow (CMY). Three CMY electroactive polymers are selected, synthesized, and first, integrated into monochromatic electrochromic devices (pixels) similar to electrochemical cells. In order to develop innovative trichromatic devices, new pixel architectures are proposed and compared. In particular, the stacking of the three monochromatic CMY electrochromic devices in a single system is declined in the form of three different electrochemical cells, which differ in the nature and positioning of the counter‐electrode. Overall performances are finally evaluated in terms of range and ease of assembly. The architecture with common counter‐electrode is clearly the one that offers the best potential for the development of electrochromic devices to reproduce a wide range of colors. [ABSTRACT FROM AUTHOR]

The effects of boiling water treatment on the physical properties of Quercus variabilis virgin cork (Qv VC) were examined and compared with those of Quercus suber reproduction cork (Qs RC). The water treatment was conducted at 100 °C for 1 h. Qv VC showed a significantly higher dimensional change in the three directions and lower weight loss than Qs RC by boiling water treatment. Untreated and boiled Qv VC showed higher density, air-dried moisture content, red/green (a*) and yellow/blue (b*) chromaticity, overall color change, shrinkage in all three directions, moisture adsorption on the entire surface, and swelling per 1% moisture content than untreated and boiled Qs RC. However, the lightness (L*) and water absorption on each surface were higher for Qs RC than for Qv VC. Moisture adsorption on each surface was comparable before and after heat treatment for both species. After boiling water treatment, the air-dried moisture content, dimensions, volume shrinkage, water absorption, and moisture adsorption on each surface and the entire surface increased, whereas L*, a*, b*, and swelling per 1% moisture content decreased. The results of the present study could be useful for further utilization of Qv cork growing in Korea. [ABSTRACT FROM AUTHOR]

Tunability of optical performance is one of the key technologies for adaptive optoelectronic applications, such as camouflage clothing, displays, and infrared shielding. High-precision spectral tunability is of great importance for some special applications with on-demand adaptability but remains challenging. Here we demonstrate a galvanostatic control strategy to achieve this goal, relying on the finding of the quantitative correlation between optical properties and electrochemical reactions within materials. An electrochromic electro-optical efficiency index is established to optically fingerprint and precisely identify electrochemical redox reactions in the electrochromic device. Consequently, the charge-transfer process during galvanostatic electrochemical reaction can be quantitatively regulated, permitting precise control over the final optical performance and on-demand adaptability of electrochromic devices as evidenced by an ultralow deviation of <3.0%. These findings not only provide opportunities for future adaptive optoelectronic applications with strict demand on precise spectral tunability but also will promote in situ quantitative research in a wide range of spectroelectrochemistry, electrochemical energy storage, electrocatalysis, and material chemistry. [ABSTRACT FROM AUTHOR]

Since the discovery of electrochemical coloration phenomenon, electrochromic devices capable of monitoring transmittance, reflectance, and absorption at designated wavelengths have embraced great achievements. The marriage of electrochemistry and optical modulation has infused fascinating properties in electrochromic devices, which find applications in thermal management, display, smart windows, and camouflage. Inspired by the multipronged advancements in electrochemical devices, the incorporation of multivalent metal ions having rich electrochemistry into electrochromic devices is bloomed in recent years. Zinc, distinguished by its high crustal abundance, suitable standard redox potential, and inherent safety, has facilitated the assembly of highly efficient electrochromic devices. Zinc anode-based electrochromic devices with dual-band (visible and near-infrared) tunability, energy retrieval functions, multi-color options, multiple working modes (transmittance mode and reflectance mode), and scalability have been prominently showcased. Here in this review, the birth of zinc anode-based electrochromic devices will be systematically narrated, starting from the discovery of electrochromic phenomenon, to the evolution of electrochromic devices, and to the latest achievements in zinc anode-based electrochromic devices. Additionally, this review delves into the future development trends and perspectives of zinc anode-based electrochromic devices. This review serves as a handbook, which summarizes the history of electrochromism, introduces the physics behind it, highlights the development in zinc anode-based electrochromic devices, and aims to inspire future endeavors into this field, particularly those focused on developing energy-efficient electrochromic devices. [ABSTRACT FROM AUTHOR]

Electrochromic devices have important applications in building energy conservation, next‐generation displaying, and security encryption, while durable and high‐performance electrochromic materials are highly desirable. Herein, a Zn‐based electrochromic smart window by using 3D ordered macroporous amorphous WO3 (a‐WO3) arrays as cathode is reported. Benefiting from a 3D ordered macroporous structure with a high specific surface area that accelerates the ion diffusion and migration, and the oxygen vacancy modulated a‐WO3 providing abundant zinc ion insertion channels, the as‐fabricated zinc‐based a‐WO3 inverse opal (a‐WO3‐IO) device exhibits excellent electrochromic properties, including large light modulation (83% optical contrast at 700 nm), fast response time (5.3 s for coloring and 3.2 s for bleaching), and robust cycling stability. Moreover, a solid‐state a‐WO3‐IO prototype electrochromic smart window is demonstrated for light modulation, electronic display, and power supply. Furthermore, experimental results and theoretical calculations reveal that 3D macroporous amorphous WO3 with rich oxygen vacancies can enhance the zinc ion absorption and diffusion, leading to the enhancement of electrochromic performance. [ABSTRACT FROM AUTHOR]

Dual‐band optical signals, consisting of visible and infrared wavelengths, hold significant potential in various fields such as night vision, vehicle safety, bioimaging, and optical communications. Consequently, considerable attention has focused on modulation techniques for visible‐infrared dual‐band signals, including various electrochromic devices. However, these devices often suffer from low speeds and complex structures, making them unsuitable for satisfying the current demand for ultrafast on‐chip nanophotonics. Here, an ultrafast, dual‐band selective optical switching is presented in thallium selenide (TlSe), a layered nanomaterial with low‐symmetry. Transient absorption microscopy directly reveals distinct modulation bands in the visible and near‐infrared (NIR) regions. Notably, these bands exhibit orthogonal polarization dependencies, enabling the selective modulation of visible and NIR light via polarization control. Theoretical analysis reveals that the modulation bands in the visible and NIR regions arise from the perpendicularly anisotropic excited‐state absorption of electrons and holes, respectively. This is supported by distinct ultrafast cooling times observed for electrons and holes. The modulations exhibit picosecond‐scale dynamics owing to efficient Auger recombination. These exceptional characteristics highlight the promising nature of low‐symmetry TlSe as a novel material for ultrafast dual‐band nanophotonics. Furthermore, this work provides fundamental insights into anisotropic carrier dynamics, including effective mass‐dependent cooling and many‐body interactions. [ABSTRACT FROM AUTHOR]

A distance-based visual electrochromic biosensing device is proposed. With this device, the naked eye is capable of discerning the distance of discoloration, which exhibits a positive correlation with the concentration of the detected substance. [ABSTRACT FROM AUTHOR]

The sol–gel process for fabricating electrochromic thin films is straightforward, offering advantages such as low cost and ease of compositional control. Herein we prepared GO–Bi–WO3 films with improved electrochromic performance using a simple sol–gel spin-coating method. The sample shows a fast-switching time (1.8 s for coloring and 1.8 s for bleaching), large optical modulation (85% at 630 nm), excellent stability (86.4% retention after 10 200 cycles), and high coloration efficiency (65.9 cm2 C−1). This work indicates the electrochromic performance of WO3-based films can be enhanced by incorporating GO, which provides an effective strategy for the rapid, safe, and efficient fabrication of electrochromic thin films. [ABSTRACT FROM AUTHOR]

VO 2 (M) films have been considered as promising thermochromic coatings for application in smart windows. Meanwhile, the comprehensive performance of the films required for practical smart windows and their large-scale preparation are still great challenges. In this study, a one-step ultraviolet (UV) photo-assisted spray pyrolysis route was developed to prepare thermochromic VO 2 (M) films on TiO 2 -buffered soda–lime glass substrates based on molecular dynamicsimulations and related experiments. According to the results, both the luminous transmittance and solar modulation efficiency of the film deposited at 450 °C and exposed to UV photo-irradiation increased by 17% and 40%, respectively, as compared to those of the non-irradiated films. In the case of VO 2 and TiO 2 single layers as well as bilayer VO 2 /TiO 2 films deposited on substrates preheated to 350 °C-550 °C, it was found that UV irradiation could promote crystallization along with regulating the phase structure, orientation, and morphology, which enhanced thermochromic performance of the photo-treated films. Therefore, photo-assisted spray pyrolysis deposition is a facile, cost-effective and scalable technology for improving the comprehensive performance of as-obtained materials, which is appealing in the large-scale preparation of VO 2 smart windows. [ABSTRACT FROM AUTHOR]

Copper metal ions (Cu2+) are widely used in various industries, and their salts are used as supplementary components in agriculture and medicine. As this metal ion is associated with various health issues, it is necessary to detect and monitor it in environmental and biological samples. In the present report, we synthesized a naphthoquinoline-dione-based probe 1 containing three ester groups to investigate its ability to detect metal ions in an aqueous solution. Among various metal ions, probe 1 showed a vivid color change from yellow to colorless in the presence of Cu2+, as observed by the naked eye. The ratiometric method using the absorbance ratio (A413/A476) resulted in a limit of detection (LOD) of 1 µM for Cu2+. In addition, the intense yellow-green fluorescence was quenched upon the addition of Cu2+, resulting in a calculated LOD of 5 nM. Thus, probe 1 has the potential for dual response toward Cu2+ detection through color change and fluorescence quenching. 1H-NMR investigation and density functional theory (DFT) calculations indicate 1:1 binding of the metal ion to the small cavity of the probe comprising four functional groups: the carbonyl group of the amide (O), the amino group (N), and two t-butyl ester groups (O). When adsorbed onto various solid surfaces, such as cotton, silica, and filter paper, the probe showed effective detection of Cu2+ via fluorescence quenching. Probe 1 was also useful for Cu2+ sensing in environmental samples (sea and drain water) and biological samples (live HeLa cells). [ABSTRACT FROM AUTHOR]

Multicolor electrochromic devices have gained attention widely. To support the development of multicolor electrochromic devices, we studied complementary combinations of a multicolor switchable polyaniline (PANI) electrode and 1-methyl-4,4′-bipyridyl iodide (MBI). In particular, MBI acting as an electrolyte and cathodic electrochromic layer can not only simplify the architecture of a device, but also support the color richness of the device simultaneously. Wide band optical modulation in visible light (58.1% at 550 nm) and near-infrared light (35% at 800 nm) confirms the advantageous optical properties of the combination, possessing a wide color gamut range over a range of working voltages adjustable for red, yellow, green, blue, and purple, each having a high color contrast of up to 73.8. This is accompanied by the excellent electrochemical performances of the mentioned combination, such as a fast response time of 1 s/1.9 s (modulating 77%-colored/bleached) with good cycle stability, and high coloration efficiency of 140.63 cm2/C. In addition, utilizing a screen-printed polyvinyl alcohol (PVA) as a masking barrier layer, it is possible to display patterned anti-counterfeit information within the application. Given these electrochromic performance properties, it is considered a readily feasible strategy to utilize PANI and MBI combination to develop novel electrochromic devices, which can be used widely in the areas of smart packaging, smart labels, and flexible smart windows associated with specific application scenarios. [Display omitted] Multicolor electrochromic devices have gained attention widely. To support the development of multicolor electrochromic devices, we studied complementary combinations of a multicolor switchable polyaniline (PANI) electrode and 1-methyl-4,4′-bipyridyl iodide (MBI). In particular, MBI acting as an electrolyte and cathodic electrochromic layer can not only simplify the architecture of a device, but also support the color richness of the device simultaneously. Wide band optical modulation in visible light (58.1% at 550 nm) and near-infrared light (35% at 800 nm) confirms the advantageous optical properties of the combination, possessing a wide color gamut range over a range of working voltages adjustable for red, yellow, green, blue, and purple, each having a high color contrast of up to 73.8. This is accompanied by the excellent electrochemical performances of the mentioned combination, such as a fast response time of 1 s/1.9 s (modulating 77%-colored/bleached) with good cycle stability, and high coloration efficiency of 140.63 cm2/C. In addition, utilizing a screen-printed polyvinyl alcohol (PVA) as a masking barrier layer, it is possible to display patterned anti-counterfeit information within the application. Given these electrochromic performance properties, it is considered a readily feasible strategy to utilize PANI and MBI combination to develop novel electrochromic devices, which can be used widely in the areas of smart packaging, smart labels, and flexible smart windows associated with specific application scenarios. [ABSTRACT FROM AUTHOR]

Conducting polymers (CPs) are conductive materials composed of organic polymers. CPs have excellent properties such as easy synthesis and effortless fabrication, tunable electrical property, high environmental stability, high mechanical and optical properties. These unique properties have attracted researchers to discover a wide variety of uses, such as batteries, solar cells, sensors, supercapacitors, electrochromic devices, and biochemical applications. Although CPs have many limitations in their pristine form, hybridization with other materials overcomes these limitations. Here in this review article, we discuss different CPs based chemosensors for colorimetric and fluorimetric detection and determination of noble metal ions (Ag+, Pd2+, Pt2+/4+, and Au3+) in different environmental, agricultural, and biological samples. Further, the sensing performances of these chemosensors have been compared and discussed. We hope this article will help the readers with the future design of CPs based optical sensor (colorimetric and fluorescent) for detecting noble metal cations. [ABSTRACT FROM AUTHOR]

VO 2 (M) films have been considered as promising thermochromic coatings for application in smart windows. Meanwhile, the comprehensive performance of the films required for practical smart windows and their large-scale preparation are still great challenges. In this study, a one-step ultraviolet (UV) photo-assisted spray pyrolysis route was developed to prepare thermochromic VO 2 (M) films on TiO 2 -buffered soda–lime glass substrates based on molecular dynamicsimulations and related experiments. According to the results, both the luminous transmittance and solar modulation efficiency of the film deposited at 450 °C and exposed to UV photo-irradiation increased by 17% and 40%, respectively, as compared to those of the non-irradiated films. In the case of VO 2 and TiO 2 single layers as well as bilayer VO 2 /TiO 2 films deposited on substrates preheated to 350 °C-550 °C, it was found that UV irradiation could promote crystallization along with regulating the phase structure, orientation, and morphology, which enhanced thermochromic performance of the photo-treated films. Therefore, photo-assisted spray pyrolysis deposition is a facile, cost-effective and scalable technology for improving the comprehensive performance of as-obtained materials, which is appealing in the large-scale preparation of VO 2 smart windows. [ABSTRACT FROM AUTHOR]

Due to their versatility and easy processing, Surface-Anchored Metal–Organic Frameworks (SurMOFs) have gained interest in recent times as promising electrochromic thin films. Herein a step forward in their use and characterization was achieved thanks to the integration of {Zn2(PDICl4)2} SurMOFs in a multi-layer electrochromic device (ECD), based on a membrane-like electrolyte. The optical and electrochemical properties of the ECD were fully characterized, revealing a two-step reduction process localized on the organic ligand and involving subsequent near infra-red (NIR) and cyan absorbing states, leading to optical modulation of the films. The species responsible for this absorption were isolated and identified in the reduced states. In parallel to experimental characterization, quantum chemistry was successfully used to investigate the structure–property relationship of the SurMOF, revealing additional information regarding the structure and the local environment of the electrochromic ligand. [ABSTRACT FROM AUTHOR]

Nickel hydroxides (monohydroxides of several modifications and layered double hydroxides, based on nickel hydroxide) have high electrochemical, electrochromic, and electrocatalytic properties that allow them to be effectively used as an active substance in alkaline batteries, hybrid supercapacitors, electrochemical sensors, for electrocatalytic oxidation of organic substances and as an electrochromic device. Each application has its specific requirements for nickel hydroxides which must be defined. For an effective application, it is necessary to carry out a targeted construction of structure and composition, and selection of characteristics of nickel hydroxides and to develop targeted methods and conditions for nickel hydroxide synthesis. The structure, properties, and methods of preparation for use in various fields of nickel hydroxide application have been considered from the targeted ternary points of view: requirements definition, types and characteristics selection, and applying the synthesis method in industry. The 3‐level hierarchical complex of mechanisms for the formation of nickel hydroxides has been described. Also, the contribution of Ukrainian scientists to research in the field of nickel hydroxides is considered. [ABSTRACT FROM AUTHOR]

A dual-band electrochromic supercapacitor device (DESCD) can be driven by an external power supply to modulate solar radiation, which is a promising energy-saving strategy and has broad application prospects in smart windows. However, traditional power supplies, such as batteries, supercapacitors, etc., usually face limited lifetimes and potential environmental issues. Hence, we propose a self-powered DESCD based on TiO2/WO3 dual-band electrochromic material and a ternary dielectric rotating triboelectric nanogenerator (TDR-TENG). The TDR-TENG can convert mechanical energy from the environment into electrical energy to obtain a high output of 840 V, 23.9 µA, and 327 nC. The as-prepared TDR-TENG can drive the TiO2/WO3 film to store energy with a high dual-band modulation amplitude of 41.6% in the visible (VIS) region and 84% in the near-infrared (NIR) region, decreasing the indoor–outdoor light–heat interaction and thereby reducing the building energy consumption. The self-powered DESCD demonstrated in this study has multiple functions of energy harvesting, energy storage, and energy saving, providing a promising strategy for the development of self-powered smart windows. [ABSTRACT FROM AUTHOR]

To mitigate Zn corrosion, dendrite growth and hydrogen evolution reactions (HER) in Zn-anode based electrochromic devices, hydrophobic CuZn5 alloy was coated on Zn@CuZn with lower nucleation potential, high coulombic efficiency, inhibited HER, and prolonged reversibility, enabling improved switching kinetics and cycling stability in an electrochromic Zn@CuZn‖‖Prussian Blue (PB) device. [ABSTRACT FROM AUTHOR]

A detailed investigation addressing the effects of functionalizing conjugated polymers with oligo(ethylene glycol) (EGn) sidechains on the performance and polymer‐electrolyte compatibility of electrochromic devices (ECDs) is reported. The electrochemistry for a series of donor‐acceptor copolymers having near‐infrared (NIR)‐optical absorption, where the donor fragment is 3,4‐ethylenedioxythiophene (EDOT) or an EGn functionalized bithiophene (g2T) and the acceptor fragment is diketopyrrolopyrrole (DPP) functionalized with branched alkyl or EGn sidechains, is extensively probed. ECDs are next fabricated and it is found that EGn sidechain incorporation must be finely balanced to promote polymer‐electrolyte compatibility and provide efficient ion exchange. Proper electrolyte‐cation pairing and polymer structural tuning affords a 2x increase in optical contrast (from 12% to 24%) and >60x reduction in switching time (from 20 to 0.3 s). Atomic force microscopy (AFM)/grazing incidence wide‐angle X‐ray scattering (GIWAXS) characterization of the polymer film morphology/microstructure reveals that an over‐abundance of EGn sidechains generates large polymer crystallites, which can suppress ion exchange. Lastly, time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) indicates sidechain/electrolyte identity does not influence the electrolyte penetration depth into the films, and EGn sidechain inclusion increases electrolyte cation uptake. The material structural design insight and guidelines regarding the polymer‐electrolyte ion insertion/expulsion dynamics reported here should be of significant utility for developing next‐generation mixed ionic‐electronic conducting materials. [ABSTRACT FROM AUTHOR]